Electrically actuated valves are used in a wide variety of modern commercial and industrial machines. Notable among such applications are those associated with internal combustion engines. In an internal combustion engine fuel system, for example, various pumps and fuel injectors or other fuel admission valves can employ electrical actuators for controlling fluid communication between two fluid conduits. It is common for such electrical actuators to include a solenoid in a valve body, operably coupled with an armature attached to a valve member whose position is desired to be controlled. Energizing of the solenoid causes the armature to move toward the solenoid, whereas deenergizing the solenoid enables the armature and valve member to move away from the solenoid, according to well-known principles. Biasers such as biasing springs and/or hydraulic biasers are employed to assist in controlling the position of the valve member. These electrically actuated valves, to control the admission of a liquid or a gaseous fuel, can be coupled with an intake conduit feeding a mixture of the fuel and air to an engine cylinder, or the fuel can be delivered directly into an engine cylinder.
The foregoing and other types of electrically actuated valve systems often require that valves move relatively quickly and repetitively. Because the travel speed of a valve member as well as the valve opening time tends to affect the rate of fuel delivery, it is generally desirable for valve motion to be relatively tightly controlled. Engineers have discovered that it is relatively straightforward to control the time at which an electrical actuator is energized, therefore a valve opening time can be relatively precisely controlled in many instances. It tends to be more challenging to precisely control a valve closing time, as a valve member returning toward a valve seat can have a travel speed and therefore valve closing time that is less predictable for a variety of reasons.
Many modern engine systems, and other mechanical systems employing electrically actuated valves, utilize sophisticated electronic control modules (ECMs). Engineers have experimented literally for decades, exploiting the capabilities of computer control and analysis, as to how to best detect the time at which a valve member “seats.” One known technique relates to sensing an electrical current property in the solenoid circuitry that is induced after the circuit is turned off. United States Patent Application Publication No. 2015/0308399A1 to Hoban Jr. et al. describes a strategy for electronic control of valves that provides for seat detection under such circumstances.
In general terms, when a circuit energizing a solenoid in the circuitry is turned off and the associated armature travels away from the solenoid toward a seated position, closing a valve seat and stopping fluid flow out of the valve, an induced electrical current may exhibit certain properties at or close to the point in time at which the valve member stops its travel upon reaching the seat. While these principles have been exploited successfully, some known techniques are relatively computationally intensive.